Industrial mining machines, such as electric rope or power shovels, draglines, etc., are used to execute digging operations to remove material from a bank of a mine or a quarry. On a conventional rope shovel, a dipper bucket is attached to a handle, and the dipper bucket is supported by a cable, or rope, that passes over a boom sheave. The rope is secured to a bail that is pivotably coupled to the dipper bucket. The handle is moved along a saddle block to maneuver a position of the dipper bucket. During a hoist phase, the rope is reeled in by a winch in a base of the machine, lifting the dipper bucket upward through the bank and liberating the material to be dug. To release the material disposed within the dipper bucket, a dipper door is pivotally coupled to the dipper bucket. When not latched to the dipper bucket, the dipper door pivots away from a bottom of the dipper, thereby freeing the material out through a bottom of the dipper.
In other words, the dipper door must be held closed while the dipper bucket is being loaded and while the load is being swung to a deposit point. At that time, the dipper is opened to allow the contents of the dipper to empty. Typically, the locking of the dipper door has been accomplished by a mechanical latch that interfaces with a wall of the bucket next to the free edge opposite the rotating attachment of the dipper bucket to the machine. The mechanical latch holds the door in a closed position, and is released by a cable, trip wire, or other device to allow the door to swing open under its own weight and the changing attitude of the dipper bucket as it rotates back in preparation for its next loading cycle.
FIG. 1 illustrates a power or mining shovel 100 as is known in the art. The shovel 100 includes a mobile base 102, drive tracks 104, a turntable 106, a revolving frame 108, a boom 110, a lower end 112 of the boom 110 (also called a boom foot), an upper end 114 of the boom 110 (also called a boom point), tension cables 116, a gantry tension member 118, a gantry compression member 120, a sheave 122 rotatably mounted on the upper end 114 of the boom 110, a dipper bucket 124, a dipper door 126 pivotally coupled to the dipper bucket 124, a hoist rope 128, a winch drum (not shown), a dipper handle 130, a saddle block 132, a shipper shaft 134, and a transmission unit (also called a crowd drive, not shown). The rotational structure 25 allows rotation of the upper frame 30 relative to the lower base 15. The turntable 106 defines a rotational axis 136 of the shovel 100. The rotational axis 136 is perpendicular to a plane 138 defined by the base 102 and generally corresponds to a grade of the ground or support surface.
The mobile base 102 is supported by the drive tracks 104. The mobile base 102 supports the turntable 106 and the revolving frame 108. The turntable 106 is capable of 360-degrees of rotation relative to the mobile base 102. The boom 110 is pivotally connected at the lower end 112 to the revolving frame 108. The boom 110 is held in an upwardly and outwardly extending relation to the revolving frame 108 by the tension cables 116, which are anchored to the gantry tension member 118 and the gantry compression member 120. The gantry compression member 120 is mounted on the revolving frame 108.
The dipper bucket 124 is suspended from the boom 110 by the hoist rope 128. The hoist rope 128 is wrapped over the sheave 122 and attached to the dipper bucket 124 at a bail 140. The hoist rope 128 is anchored to the winch drum (not shown) of the revolving frame 108. The winch drum is driven by at least one electric motor (shown schematically as 141 in FIG. 1) that incorporates a transmission unit (not shown). As the winch drum rotates, the hoist rope 128 is paid out to lower the dipper bucket 124 or pulled in to raise the dipper bucket 124. The dipper handle 130 is also coupled to the dipper bucket 124. The dipper handle 130 is slidably supported in the saddle block 132, and the saddle block 132 is pivotally mounted to the boom 110 at the shipper shaft 134. The dipper handle 130 includes a rack and tooth formation thereon that engages a drive pinion (not shown) mounted in the saddle block 132. The drive pinion is driven by an electric motor and transmission unit (not shown) to extend or retract the dipper handle 130 relative to the saddle block 132.
An electrical power source (not shown) is mounted to the revolving frame 108 to provide power to a hoist electric motor (not shown) for driving the hoist drum, one or more crowd electric motors (not shown) for driving the crowd transmission unit, and one or more swing electric motors (not shown) for turning the turntable 106. In some cases, electric motor 141 powers all of the moving components of the shovel. Each of the crowd, hoist, and swing motors is driven by its own motor controller, or is alternatively driven in response to control signals from a controller 142.
FIGS. 2 and 3 illustrate a dipper door trip assembly that includes a linkage assembly 144 for the shovel 100. The dipper door trip assembly and linkage assembly 144 releases the dipper door 126 from the dipper bucket 124 and allows the dipper door 126 to pivot away from a bottom of the dipper bucket 124. Although the dipper door trip assembly and linkage assembly 144 is described in the context of the power shovel 100, the dipper door trip assembly and linkage assembly 144 can be applied to, performed by, or used in conjunction with a variety of industrial machines (e.g., draglines, shovels, tractors, etc.).
With continued reference to FIGS. 2 and 3, the linkage assembly 144 includes a further pivot structure 146, such as a bolt or rod (not shown clearly) coupled to the lever arm 148. The pivot structure 146 receives an end of the actuation element (e.g., receives a link of a chain of the actuation element 149), allowing the actuation element to pivot relative to the lever arm 148 as the actuation element is moved by the trip motor 143 (see FIG. 1). This structure may be referred to as a tripping mechanism interface where the tripping mechanism is attached to latching mechanism of the door. The pivot structure 146 is sized and shaped to absorb a substantial amount of stress generated by the pulling force of the actuation element on the lever arm 148 as the actuation element is moved by the trip motor.
With reference again to FIG. 3, the linkage assembly 144 further includes a rod 150 pivotally coupled to the lever arm 148. The rod 150 includes a first end 152 that is received at least partially within the lever arm 148 and pivots about a pivot structure 146 coupled to the lever arm 148, such that the rod 150 is able to pivot relative to the lever arm 148. The rod 150 further includes a second end 154 that is coupled to a latch lever bar 156 of the linkage assembly 144. As with the first end 152 though not clearly shown, the second end 154 also includes a spherical bearing or bushing 158 that receives an end 160 of the latch lever bar 156, thereby creating a spherical joint between the rod 150 and the latch lever bar 156 that permits freedom of movement and rotation of the rod 150 about multiple axes relative to the latch lever bar 156. Other constructions include a different type of joint between the rod 150 and the latch lever bar 156 (e.g., a ball joint, etc.).
With reference to FIGS. 1-4, in order to release the dipper door 126 from the latched condition, the trip motor 143 is activated by the controller 142 (see FIG. 1 in particular). When the trip motor 143 is activated, the trip motor 143 pulls an actuation element 149 toward the trip motor 143, thereby causing the lever arm 148 to pivot relative to the pivot structure 146, which causes the rod 150 to move. As the rod 150 is moved, the spherical joints at the first end 152 and the second end 154 of the rod 150 permit relative rotational movement between the rod 150 and both the lever arm 148 and the latch lever bar 156, accounting for any pivoting and arching movement of the lever arm 148 about the pivot structure 146.
As the rod 150 moves generally both rotationally and linearly, the movement of the rod 150 generates a generally rotational movement of the latch lever bar 156, and the movement of the latch lever bar 156 generates a generally linear movement of the latch bar 162. As the latch bar 162 is moved upwardly as shown in FIGS. 2 and 3, the latch bar insert 164 is pulled away from the dipper bucket 124 (see FIG. 4), thereby freeing the dipper door 126 from the dipper bucket 124 by removing the latch bar from a channel found on another part of the bucket such as the bottom wall (see FIG. 4), and allowing the dipper door 126 to swing and pivot open relative to the bottom of the dipper bucket 124 to unload material. As the material is unloaded, for example, into a truck or other vehicle, the components of the dipper door trip assembly and linkage assemblies are positioned to remain well away from the truck and to not interfere with the unloading process.
To return the latch bar insert 164 back into the channel 166 after the material has been unloaded (see FIG. 4), gravity is used (i.e., the latch bar 162 is naturally urged toward the latched position by gravity). In other constructions, a biasing member or members are used to urge the latch bar 162 and the latch bar insert 164 toward the latched position. Because of the high mechanical advantages and forces possible with the dipper door trip assembly and linkage assembly described above, the latch bar insert 164 may be safely extended deep into the channel 166 during this latched condition. This results in a significantly lower likelihood of a false trip and release of the dipper door 126.
Focusing on FIGS. 1 and 4, it can be generally seen that the dipper bucket 124 comprises a shell 168 that includes a bottom wall 170, a top wall 172, and side walls 174 that define an opening 176 and the majority of the enclosed space (bounded on four sides) for holding material. The shell may be made from separate components that are attached to each other or may be made of an integrally cast component, etc.
Turning now to FIG. 5, a dipper door 178 used as part of a dipper bucket on a machine sold under the TRADENAME “7495 Electric Rope Shovel” by the assignee of the present disclosure is shown. The mechanism used to hold the door closed, the general construction of the bucket and operation of the machine are generally similar to that previously described with respect to FIGS. 1 thru 4, except that the exact devices and methods of operation are not the same. That is to say, the door is held closed and is opened on the bucket and the machine uses a mechanical system to effectuate this locking and unlocking in a manner similar to what has been described although not exactly the same.
Likewise, the manner in which the shovel works in moving material from one location to another using the bucket, door and latching mechanism is similar to what has been already described. It is to be understood that any variation of a locking mechanism known or that will be devised in the art may be used with any of the embodiments discussed herein and any machine that moves material may use any of the embodiments discussed herein. Consequently, the description given with reference to FIGS. 1 thru 4 is by way of example only and is intended only to provide a general understanding to the reader on how various embodiments of the present disclosure are used and constructed.
Looking at the construction of this dipper door 178 in FIG. 5, it can be seen that includes a substantially flat base 180 that defines the height H (measured along the Y axis of the Cartesian coordinates as shown) and width W (measured along the X axis of the Cartesian coordinates as shown) of the door. The exterior surface 182 of the flat base can be seen, so called as it faces away from the interior of the bucket where material is stored during excavation. Hinge points 184 are located near the upper end 186 of the flat base 180 defined by flanges 187 that extend upwardly along the Y direction and then in a direction that is toward the interior of the bucket (−Z direction) when the door is installed on the bucket. A reinforcing pad 188 is located near the free or lower end 190 of the base that is opposite the upper end 186. Reinforcing gussets 192 extend from the side of the reinforcement pad 188 toward the free end 190 of the base 180. A latching guide 194 is housed inside of the reinforcing pad 188 that provides a place for a latch bar to move up and down to lock and unlock the door as previously described. This latching guide includes a channel 196 that opens along the lower free end 190 of the base plate 180 through which a latching member can extend to lock the door.
Three reinforcing ribs 198 extend from the reinforcing pad 188 in an upward Y direction and terminate near the top edge 186 of the flat base 180 into a horizontal stiffening rib 200 that extends along the top edge 186 of the flat base 180 along the X direction. Looking at FIG. 5, the side of the right most rib 198a includes a through slot 202 for accommodating the latch level bar for the latching mechanism as previously described. Similarly, the center vertical reinforcing rib 198b includes a slot 204 through its upper surface and a through slot 206 through the entire rib in the general −X direction to contain or allow movement of various parts of the latching mechanism. The leftmost vertical reinforcing rib 198c has no slots in it as the latching mechanism does not need to engage this structural member.
Accordingly, all three vertical reinforcing ribs 198 have different construction that necessitate different parts that are welded to each other and the base plate 180. In fact, the door 178 is essentially a series of sheet metal components that are welded onto the flat base. It should be noted that the middle portion of the horizontal rib 200 and the center vertical rib 198b are recessed as compared to the top surfaces of the flanges 187 and other two vertical ribs.
As can be imagined, the bucket that uses the door of FIG. 5 needs to be adjusted in size so that different fill capacities may be provided for various applications in the field. For example, dipper bucket sizes may vary from 46 cubic yards to 89 cubic yards for the 7495 Electric Rope Shovel. Furthermore, the shape of the buckets may vary such as having straight sides or have a trapezoidal shape, which is referred to as a FastFil configuration in the art. To account for these different sizes and shapes, the height, shape, or other dimensions or characteristics of the door must be changed. Specifically, the door height is often varied which requires dimensional changes to 10 different parts or components.
Looking at FIG. 5, the components that need to be changed dimensionally along the Y axis include the base 180, top panel 208 of right rib 198a, right side panel 210 of right rib 198a, left side panel 212 of right rib 198a, top panel 214 of center rib 198b, right side panel 216 of center rib 198b, left side panel 218 of center rib 198b, 220 top panel 220 of left rib 198c, right side panel 222 of left rib 198c, and left side panel 224 of left rib 198c. This requires more parts to be stocked in inventory and also more time to manufacture doors of various sizes. This leads to an undesirable increased cost and lead time for each sized door.
Now focusing on FIG. 6, a known latch mechanism 226 construction is shown that is used with the door 178 of FIG. 5. The right rib 198a can be seen and the latch lever bar 228 extends through this slot 202. At the right end of the latch lever bar 228, part of the latch tripping mechanism or tripping mechanism interface 230 may be seen. At the left end of the latch lever bar 228, a pivot connecting portion 232 of the latch lever bar can be seen that is pivotally mounted to structure found in the middle vertical stiffening rib 198b. The latch lever bar 228 passes through the slot of the yoke 234 of the latch bar 236. When the latch tripping mechanism 230 is activated, the right of the of the latch lever bar 228 moves upward causing the latch lever bar to rotate upwards about the pivot point 238 defined by the pivot connecting portion until it contacts the upper end of the yoke 234 of the latch bar 236, pulling the bar upwards until the door is unlocked. Deactivation of the tripping mechanism causes this process to reverse itself until the door is locked once more. Two mounting plates 240 are attached via welding proximate the upper end of the slot 202 and lower end of the slot 202 found in the right vertical reinforcing rib 198a. Bumper stops 242 are attached to the mounting plates 240 that limit the travel of the latch lever bar 228 upwardly and downwardly. A protrusion 244 is found on the lower edge of the latch lever bar 236 that is configured to contact the lower bumper before the latch lever bar bottoms out in the slot 202. The top edge of the latch lever bar lacks such a protrusion but includes a recess 246 on the yoke interface portion 248 of the latch lever bar 228 where contact is made between the latch lever bar 228 and the latch bar 236. It has been found that this latching mechanism experiences wear problems in the field, necessitating replacement.
Accordingly, it is desirable to reduce the cost of door manufacture by reducing the number of parts that are changed to make doors of various sizes and to decrease the time to manufacture each door. In turn, this should reduce the lead time to supply various sized doors to a customer. Furthermore, it is desirable to improve on the current latching mechanism to reduce field replacement.